Self-regulating brushing tool



May 26, 1964 V. K. CHARVAT SELF-REGULATING BRUSHING TOOL Filed May 51,1961 INVENTOR.

VERNON K. CHARVAT Qberlimmnk OMEHH ATTORNEYS United States Patent3,134,122 SELF REGULATING BRUSHING TOOL Vernon K. Char-vat, Bay Village,Ohio, assignor to The @sborn Manufacturing Company, Cleveland, Ohio, acorporation of ()hio Fiied May 31, 1951, Ser. No. 113,838 11 Claims.(Cl. 15-179) This invention relates as indicated to a self-regulatingbrushing tool, and more particularly to a power driven rotary brush, thebristles of which are assembled and treated in a novel manner to enhancethe effectiveness of the tool.

By assembling a plurality of generally parallel brush bristles such aswire monofilaments in slightly spaced sideby-side relationship andinterconnecting the same by means of a generally continuous layer offlexible plastic, brushing fingers may be produced which when assembledinto an annular back, for example, provide a rotary brush having certainvery desirable characteristics. In the first place, by thus embeddingthe bristles in the flexible plastic, it becomes feasible to employquite hard bristle materials such as steel wire having a Knoop hardnessof 700, without danger of excessive long fracture of the bristles andconsequent rapid disintegration of the brush in use. Such hard bristlematerial, of course, is capable of much more rapid cutting action on thework than are bristle materials conventionally employed.

Furthermore, by thus incorporating the bristles in relatively thin,generally flat flexible plastic fingers, such bristles may still bepermitted to fiex substantially throughout their length in contrast tocertain other brushing tools wherein the bristles may be substantiallyentirely embedded in a large body of elastomeric material.

It is preferred to employ straight bristle material rather than thecommonly employed crimped wire for several reasons including the factthat very hard wire bristles are not capable of being satisfactorilycrimped. It is also preferred that the bristles extend substantiallyradially outward from a central rotatable hub in the case of wheelbrushes, for example, and when crimped Wire bristles are employed, theworking ends of certain of the bristles will be inclined in thedirection of rotation of the tool and will therefore gouge the work,whereas the Working ends of certain of the other bristles will berearwardly inclined and will simply drag across the work surface.

When very hard brush bristles are embedded in relatively thin flexibleplastic fingers, they may nevertheless occasionally break at pointssubstantially spaced from their outer working ends but the plasticmaterial may still suflice to retain the broken portions in the brush.When operating at high speeds of rotation and when a number of the hardbristles break, however, there may be danger of a substantial portion ofa brushing finger breaking out of the brush, and it is an object of thepresent invention so to modify such fingers as to reinforce the same forretention in the brush in the event of long fracture of the hardbristles contained within such fingers.

Another object is to provide modified flexible brushing fingers havingstraight parallel brush filaments embedded therein, which fingers havemodified surface contours assisting in securing such fingers together ina central assembly and also in affording an improved brushing action.

Still another object is to provide a brushing tool wherein the bristlesand especially hard monofilaments are mounted in a manner facilitatingtheir controlled flexing in the direction of rotation of the brushingtool while at the same time greatly limiting lateral movement of suchfilaments.

A further object is to provide an annular rotary brush section having asupport portion and brush material extending radially outwardlytherefrom so formed and proportioned that when a plurality of such brushsections are assembled in closely packed axial alignment there will beno appreciable regions of reduced bristle density in the resultantcylindrical brush face corresponding to the regions of lateral interfacecontact of the annular supports.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said inventionthen comprises the features hereinafter fully described and particularlypointed out in the claims, the following description and the annexeddrawing setting forth in detail certain illustrative embodiments of theinvention, these being indicative, however, of but a few of the variousways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is an end view of a power driven rotary brush representing apreferred embodiment of the principles of this invention;

FIG. 2 is an enlarged fragmentary semi-diagrammatic View of a modifiedbrush bristle adapted to be employed in forming the brushing fingers ofthis invention;

FIG. 3 is a transverse section taken on the line 33 on FIG. 2;

FIG. 4 is a plan view of an array of parallel filaments in accordancewith FIG. 2 bonded together by a thin layer of additional plastic toform elongated generally flat flexible strips suitable for employment inthe production of brushing fingers, such additional plastic beingindicated as transparent better to disclose the beaded filaments bondedthereby;

FIG. 5 is a fragmentary transverse section taken on the line 55 of FIG.4, on an enlarged scale;

FIG. 6 is a transverse section through the brushing tool of FIG. 1, onan enlarged scale;

FIG. 7 is a further enlarged fragmentary semi-diagrammatic view of abrushing element of this invention showing a portion of thework-engaging end thereof; and

FIG. 8 is a fragmentary cross-section on an enlarged scale taken on theline 8-8 on FIG. 7.

Referring now more particularly to said drawing and especially FIGS.2-5, thereof, I prefer to utilize beaded wire bristle material of thetype disclosed in my prior copending application Serial No. 86,378,filed February 1, 1961, for Brush and Brush Material, now Patent No.3,090,061 dated May 21, 1963, in preparing the brushing fingers of thepresent invention. Thus, the hard wire monofilament 1 may have plasticheads 2 adhered thereto at intervals therealong with the interveningportion of the filament coated with a much thinner layer 3 of theplastic, or, if desired, the surface of the monofilament may be exposedintermediate such beads. As explained more in detail in my aforesaidapplication Serial No. 86,378, a wide variety of brush bristle materialmay be utilized including steel Wire having a Knoop hardness in excessof 600 and preferably in excess of 700 or even 800, other metal wiresuch as stainless steel wire, glass monofilaments and the like. A widevariety of plastic materials may be utilized to form the beads 2 and theintervening coatings 3 including nylon, polyurethane, neoprene(polychloroprene), and polyvinyl chloride. Foamed polyurethane andpolyurethane rubber have been found especially satisfactory. Suchplastic may be further bonded to the bristle 1 by means of variouswell-known bonding agents such as Ty-PlyS for bonding rubber andrubber-like materials, and epoxy resins for bonding nylon.

Abrasive granules may, if desired, be incorporated in the plastic heads2, to be released at the brush face as the bristles Wear back in use.Such granular abrasive may, for example, include aluminum oxide (Alundumor Aloxite), silicon carbide (Carborundum, Corun- 3 dum), chrome oxide,natural abrasives (e.g., pumice, emery), and mixtures of these.

:Uniform spacing of the beads 2 along the filament is not necessary, andsome irregularity of spacing is, in fact, preferred. In a typicalpreferred embodiment, the bristles 1 may be .0118 diameter carbon steelwire coated with polyvinyl chloride and provided with beads of the samematerial, such beads being about 7 in length and occurring at afrequency 'of from about three to about six per linear inch of thebristle length.

A plurality of such beaded bristles may be arranged in parallel arraybut one bristle in thickness and then bonded together as shown in FIG. 4by addition of a small amount of plastic which may be of the same typeas that already previously employed to form such heads 2 although itwill generally be preferred to employ plastic material for this purposewhich will separate between the outer working ends of the bristles inuse. A continuous elongated substantially fiat plastic band or strip 4may thus be produced in which the parallel brush filaments :1 areembedded and extend. longitudinally, insuificient additional plasticbeing employed to submerge the beads 2 which persist as smallprotuberances or surface rugosities as shown in FIG. 5 in enlargedcross-section. This band or strip 4 may now be cut into desired lengthsto form the flexible brushing fingers 5 of this invention.

In the preferred embodiment of the invention illustrated in FIGS. 1 and6 of the drawing, a large number of such brushing fingers are arrangedto form an annulus with such fingers lying in radial planes parallel tothe axis of such annulus and with the radial-1y inner ends of suchfingers closely packed together in order that a maximum number offingers may thus be employed. The inner end portions of the fingers arethen bonded together with a compatible plastic or cement to form acontinuous inner annular support 6. Thus, for example, if the plasticfingers are formed of nylon, such inner annular support may be producedby bonding the closely packed inner end portions of the fingers togetherwith an epoxy resin. As shown, the hard straight wires are thussupported and secured in the finished annular brush section withoutlocal bending which would tend to produce concentrations of stress andearly fracture when repeatedly rapidly flexed in use.

Now referring more particularly to FIGS. 7 and 8, a generally flatflexible plastic finger 5 is shown comprised of a single row of straightbristle filaments 1 having plastic beads 2 securely adhered thereto,such beaded filaments being joined together by and embedded in plasticmaterial 4 to form thin generally flat flexible fingers 5. Such plastic4 is sufficiently thin Where it interconnects adjacent filaments (FIG.8) and/or has relatively low toughness and tensile strength so that itwill tend to erode away and separate from between the outer end portionsof the bristles in use to expose the latter with their heads 2 stillbonded thereon. As best shown in FIG. 8, such thin plastic regionsinterconnecting adjacent parallel filaments result in the formation ofgrooves extending longitudinally of the fingers parallel to suchfilaments, with corresponding ridges where such filaments are embedded.The working ends of the fingers may be initially prepared in thismanner, if desired, by subjecting the same to the action of anappropriate power driven rotary brush. Thus, the beads 2 may be ofpolyurethane firmly bonded to the bristles which may be hard straightwire bristles having a Knoop hardness of at least 700, and the plasticmaterial 4 forming the flexible plastic finger in which the bristles areembedded may be of sponge neoprene (polyohloroprene) which may furthercontain filling material enhancing the erodability of the spongeneoprene upon engagement with the work under operating conditions. itwill be appreciated that the term beads as used herein and in the claimsis not intended to be limited to apertured bodies threaded on thebristles but rather includes spaced globules and protuberances adheredto the bristles and which are not necessarily concentric therewith. Withflexible brushing fingers of the type shown in FIG. 7, for example, itis possible to achieve very superior brushing characteristics; hardstraight bristle wire is suitable for employment, since the disadvantageof long fracture may be largely avoided; the protruding bristle endportions are adapted to operate upon the work in the manner of a truebrush in view of the fact that they are capable of individual fiexure indirections circumferential of the tool (FIG. 1); and yet lateralmovement of such protruding bristle end portions is very much limited bythe beads 2 thereon so that when any bristle end encounters a surfacerugosity on the work as the brushing tool rotates thereagainst, it willpass directly over such rugosity with consequent abrading action thereonrather than tending to deviate around such rugosity as has otherwisebeen the case in the past. This latter feature is of especial importancewhen brushing to produce a radius on the edge of a metal work-piece, forexample. Prior brushing tools having a fast and eificient cutting actionhave tended to produce something of a saw-tooth effect under suchcircumstances. It might be said that the brushing tool of this inventionas exemplified in FIG. 7 is one having a long trim effectcircumferentially of the brush (inasmuch as the brushing fingers arecapable of flexing in such direction for substantially their entirelength) and a short trim effect laterally of the brush (inasmuch as suchfingers are capable of very little flexing in their own plane and theprotruding bristle end portions are likewise limited by heads 2 so faras lateral flexing is concerned). It will be appreciated that FIG. 7 ofthe drawing is semi-diagrammatic in character and that portions of theplastic material 4 may also adhere to the bristle end portions eventhough the plastic material 4 has separated between such end portions.

As shown in FIG. 5 of the drawing, the bristles 1 em bedded in theflexible plastic fingers may desirably be slightly offset one fromanother in a generally zigzag manner rather than forming a perfectlystraight alignment. Such relative oifsetting of the brush bristlefilaments (in a direction circumferentially of the tool as shown in theFIG. 1 embodiment) may ordinarily be in an amount approximately equal tothe diameter of such filaments and even a little more, up to about .01inch in the case of the typical preferred embodiment in which thebristles are .0118 inch diameter carbon steel wire. Even a very smalloffset such as .005 inch is appreciably advantageous in effectingimproved operating results, the faces of the finger having acorresponding zigzag conformation in cross-section as indicated in FIG.5. More particularly, such arrangement of the bristles assists insnubbing flexure of the fingers in a circumferential direction when thePEG. 1 embodiment of the invention is rotated at high speed inengagement with the work, and the working ends of the individualbristles are prevented from skipping and bouncing upon impact againstthe work surface. Consequently, a controlled brushing action is obtainedwherein each bristle tip is caused to travel in a substantially straightline across the work surface to produce a finish more nearly similar tothat obtained with other types of abrading tools such as conventionalabrasive belts, for example. This type of action is much preferred incertain commercial abrading operations such as the removal of solderfrom automobile bodies and the like. The brushing tool of this inventionaccordingly has a high degree of lateral stability and yet the brushmaterial is enabled to flex in a circumferential direction with suchlatter flexibility, however, diminishing in increments toward thecentral support.

In view of the foregoing, it is now possible to provide high speedrotary brushing tools utilizing hard and therefore very effectivebristle materials without decreased brush life due to long fracturethereof and without production of a non-uniform and inferior surfacefinish which would normally be anticipated when employing suchmaterials. Certain subject matter disclosed but not claimed herein isdisclosed and claimed in my co-pending application Serial No. 347,881entitled Self-Regulating Composite Brushing Tool, filed February 27,1964.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

I therefore particularly point out and distinctly claim as my invention:

1. A brushing tool comprising a support, thin flexible plastic fingerssecured thereto and extending therefrom, and a single row of parallelbrush bristle filaments embedded in said fingers extendinglongitudinally thereof, said plastic fingers having a multitude of smalllocal plastic protuberances on their faces, said protuberances beingspaced from each other both laterally and longitudinally of saidfingers, and said protuberances being thereby adapted to space adjacentfingers somewhat apart and regulate interaction of said fingers.

2. The tool of claim 1, wherein said brush material comprises a singlerow of parallel brush bristle filaments extending longitudinally of saidfingers, and the surfaces of said fingers have longitudinally extendinggrooves between and parallel to said filaments with said protuberancesprojecting from the corresponding ridges intermediate such grooves.

3. A rotary brushing tool comprising a rotatable support and brushingelements secured thereto and extending generally radially outwardlytherefrom, said elements comprising thin generally flat flexible fingersdisposed in planes parallel to the axis of rotation of said tool andclosely compacted in the region of said support, hard wire bristlesembedded in said fingers longitudinally thereof with said wire bristlesin any one finger extending parallel to one another in a single row, anda multitude of small local plastic protuberances on the faces of saidfingers, said protuberances being spaced from each other both laterallyand longitudinally of said fingers, and said protuberances being therebyadapted to regulate interaction of the latter.

4. A rotary brushing tool comprising a rotatable annular plastic supportof rectangular cross-section and brushing elements embedded in saidsupport and extending radially outwardly therefrom, said elementscomprising thin, flexible, generally fiat rectangular plastic fingersformed of plastic beaded metal wires bonded together by plastic andextending parallel to one another longitudinally of said fingers andradially outwardly from said support, the diameter of said annularsupport being substantially greater than the length of said fingersprotruding therefrom, and the width of said fingers being the same asthe width of said support, said plastic fingers having a multitude ofsmall local plastic protuberances on their faces spaced from each otherboth laterally and longitudinally of said fingers.

5. A brushing tool comprising a support, thin generally flat flexibleplastic fingers secured thereto and extending therefrom, a single row ofbrush bristles embedded in each of said fingers and extendinglongitudinally thereof, and a multitude of small longitudinally spacedprotuberances on said individual bristles, the plastic beingsulficiently thin that the outer end portions of said bristles areadapted to separate one from another by progressive separation of theplastic of said fingers therebetween upon operative engagement with thework and said protuberances appear on the faces of said fingers.

6. A rotary brushing tool comprising a rotatable support portion and aplurality of generally flat thin flexible plastic fingers extendingtherefrom, said fingers having a single row of parallel bristle elementsembedded therein, and said bristle elements having small beads securedthereto at closely spaced intervals therealong, the plastic material ofsaid fingers being adapted to separate between the outer end portions ofsaid bristle elements in use to cause said end portions to extendtherefrom with the individual movements of said end portions regulatedand limited by said beads thereon, said beads producing correspondingprotuberances on the faces of said fingers.

-7. A rotary brushing tool comprising a rotatable support portion and aplurality of closely packed generally flat thin flexible polyurethaneplastic fingers extending therefrom in radial planes relative to theaxis of rotation of said support portion, said fingers each having asingle zigzag row of straight parallel slightly spaced wire bristlesembedded therein and extending longitudinally thereof, said bristleshaving a Knoop hardness of at least 700, and small plastic beadssecurely adhered to said bristles at closely spaced intervalstherealong, said beaded bristles protruding a short distance from theouter working ends of said fingers.

8. A brushing tool having a number of adjacent thin generally fiatflexible plastic fingers, each said finger having a single zigzag row ofparallel brush bristle filaments embedded therein and extendinglongitudinally thereof, the faces of said finger having a correspondingzigzag conformation in cross-section.

9. The tool of claim 8, wherein said individual filaments have amultitude of small protuberances thereon.

10. A rotary brushing tool comprising an assemblage of thin generallyfiat flexible plastic fingers, each said finger having a single zigzagrow of brush bristle filaments embedded therein and extendinglongitudinally thereof, with the faces of said finger having acorresponding zigzag conformation in cross-section, said fingers lyingin radial planes relative to the axis of rotation of said tool, and amultitude of small protuberances on said individual filaments, saidbristle filaments with said protuberances thereon protruding a shortdistance from the outer working ends of said fingers.

11. A rotary brushing tool comprising a rotatable support portion and aplurality of generally fiat thin flexible plastic fingers closely packedaround the entire circumference of said support portion and extendingtherefrom in radial planes relative to the axis of rotation of saidsupport portion, said fingers each having a plurality of parallellongitudinally extending bristles embedded therein, and a large numberof small random plastic protuberances on the opposed generally flatfaces of said fingers spaced both longitudinally and laterally of saidfingers to regulate the interaction of said fingers.

References Cited in the file of this patent UNITED STATES PATENTS205,374 Foss June 25, 1878 2,171,805 Picard Sept. 5, 1953 2,642,705Jensen June 23, 1953 2,807,825 Gardner Oct. 1, 1957 2,818,691 LeggettJan. 7, 1958 2,917,779 Kurzke Dec. 22, 1959 2,984,053 Peterson May 16,1961

1. A BRUSHING TOOL COMPRISING A SUPPORT, THIN FLEXIBLE PLASTIC FINGERSSECURED THERETO AND EXENDING THEREFROM, AND A SINGLE ROW OF PARALLELBRUSH BRISTLE FILAMENTS EMBEDDED IN SAID FINGERS EXTENDINGLONGITUDINALLY THEREOF, SAID PLASTIC FINGERS HAVING A MULTITUDE OF SMALLLOCAL PLASTIC PROTUBERANCES ON THEIR FACES, SAID PROTUBERANCES BEINGSPACED FROM EACH OTHER BOTH LATERALLY AND LONGITUDINALLY OF SAIDFINGERS, AND SAID PROTUBERANCES BEING THEREBY ADAPTED TO SPACE ADJACENTFINGERS SOMEWHAT APART AND REGULATE INTERACTION OF SAID FINGERS.